Synthesis and molecular structure of the cationic samarium phenoxide complex [(ArO)2Sm(DME)2][BPh4] · THF and its catalytic activity for the polymerization of ε-caprolactone

Abstract The first cationic samarium phenoxide complex, [(ArO) 2 Sm(DME) 2 ][BPh 4 ] · THF (ArO = 2,6-di-tert-butyl-4-metyl-phenoxide) ( 1 ), has been synthesized by one-electron oxidation reaction of (ArO) 2 Sm(THF) 3 with AgBPh 4 in high yield and structurally characterized. The complex 1 can be used as a single-component catalyst for the ring-opening polymerization of e -caprolactone ( e -CL) with high activity. The activity of the complex 1 is much higher than that of the parent neutral complex (ArO) 3 Sm(THF) 2 , and is comparable to that of the divalent complex (ArO) 2 Sm(THF) 3 . A coordination-insertion polymerization mechanism was supposed according to the end-group analysis.